Heating ingots



c. H. WEST HEATING INGOTS June 28, 1949.

3 Sheets-Sheet 2 Filed Oct. 20, 1944 Car/H Wesf June 28, 1949. c. H.WEST 2,474,504

' HEATING INGOTS Fild Oct. 20, 1944 I 3 Sheets-Shet 3 Fig. 3.

INVENTOR {7 Car/ H Wes? Patented June 28,

Pica

HEATING mqo'rs cm fewest, St. cmmme, om, aesignor u 'Blaw-Knox Company,Pittsburgh, 2a., a eor poration. of New Jersey Application October 20,1944, Serial No. 559,500

This invention relates to heating ingots and more particularly toimparting to ingots a uniform penetrant heat' prior to rolling theingots in a'blooming mill. The invention further relates" recognized formany years but which have not,

heretofore been satisfactorily overcome. Among these disadvantages arethe washing of ingots (the melting of scale on the ingots due toexcessive heat in the heating chamber), the burning of localizedportions of ingots due to hot spots" and the very high initial andupkeep cost of soaking pit furnaces.

Ingot washing is one of the greatest disad-' vantages of theconventional soaking pit and one which has never been satisfactorilyovercome prior to my invention. It is due to the development in theheating chamber, of excessive temperatures-i. e., temperatures which areabove the melting point of the scale formed on the ingots-resulting'inmelting of the scale and consequent oxidizing of additional layers ofthe ingot, the ultimate result being substantial loss of tonnage.Moreover, the washed or melted scale runs downinto the furnace bottomwhere it seriously interferes with furnace operations and necessitatesshutting down the furnace at intervals for cleaning and repair.

So far as I am aware the theory has heretofore been universally heldamong those skilled in the art of heating ingots in preparation forrolling that in order tosubject the ingots to a uniform penetrant heatit is necessary to burn the fuel in a combustion chamber separate fromthe heating chamber and conduct the more or less bumed gases into theheating chamber. The fact is, however, that this is exactly the wrongway of heating ingots for the purpose in question. It is difficult orimpossible to avoid hot spotslocalized portions of the ingots whichbecome overheated. It is dimcult to control the flame temperature andthe temperature of the gases in the heating chamber. Apparently unburnedparticles of the fuel pass into the heating chamber where they llinvention will become apparent as the following 1 Claim. (Cl. 263-43).are burned in intimate contact with the ingots under such conditions asto create undesirably high temperatures, resulting in washing of the in-I have discovered that, quite the opposite from heating ingots inconventional, soaking pits as has heretofore been considered necessary,the long existing problems can be solved and remarkably improved resultsobtained by heating the ingots by introducing unburned combustiblematerial into the heating chamber wherein the ingots are disposed andburning the combustible material in said chamber in close proximity tothe ingots. I preferably introduce unburned combustible material intothe heating chamber through jets directed so as to deliver the'materialalongside the ingots in said chamber and I provide for burning the thusintroduced combustible material in the heatingchamber. Desirably theunburned combustible material is introduced in a plurality of streamsdirected so as to substantially uniformly distribute the combustiblematerial about or among the ingots.

I flnd that the burning of the combustible material in the heatingchamber in close proximity to the ingots results in avoiding thecreation in the heating chamber of the high temperatures which causeingot washing. While I do not limit myself to any theory of action, Ibelieve that the reason for this is that the ingots absorb heat from.the flame before the flame can attain the undesirably high temperaturewhich brings about washing. 1 I

By properly arranging the jets or burners I can produce in the heatingchamber a much more uniform controlled heat than can be produced in aconventional soaking pit. The chemical composition of the gases and theflame temperature are thus maintained remarkably uniform with the resultthat the ingots are heated in a highly eflicient manner and at the sametime more rapidly than is possible in a soaking pit.

I preferably introduce the fuel into the heating chamber through burnersarranged in the furnace wall so that combustion of the fuel commencesnot earlier than approximatelyas the fuel enters the chamber. The fueland air for supporting combustion may be mixed in the burnchamber andburned there.

. I 3 description of a present preferred embodiment thereof and apresent preferred method of practicing the same proceeds.

In the accompanying drawings I have shown a present preferred embodimentof the invention and have illustrated a present preferred method of-.practicing the same, in which Figure 1 is a vertical longitudinalcross-- sectional view through an ingot heating furnace,

Figure 2 is a horizontal cross-sectional view through the furnace shownin'Figure '1,

opposed side walls 4 and opposed end walls 5.

The side and end walls form a substantially horizontally closed chamberfor heating ingots disposed on the hearth 3. The furnace is closed by acover 6.

The furnace shown differs from a conventional soaking pit in that thereis no combustionchamber separate from the heating chamber and thefurnace is not of the regenerative type. .The

fuel is introduced directly into the heating The products. of combustionpass out through an offtake I.

The burners are arranged in the side walls 4' as clearly shown inFigures 2 and 3. In the embodiment shown in the drawings each side wallhas disposed alternately therealong series of three superposed burners 8and single burners 8.

The burners 8 are directed straight inwardly of the wall. The burners 9direct the fuel downwardly and inwardly. A burner 8 in one of the sidewalls 4 is opposite a burner 9 in the opposed side wall. n the otherhand, it may be opposite a series of burners 8 in the opposed sidewall.The arrangement of all the burners is such that when fuel is admittedthrough them simulta neously and burned within the heating chamber asubstantially uniform condition of temperature throughout the heatingchamber is obtained.

Fuel is supplied to the burners in each side wall 4 through a pipe I 0and air through a pipe ll. Branch pipes lead from the pipes III and 'IIto the respective burners as clearlyshown in Figures 2, 3 and4.

Each of the burners is disposed and mounted within the wall 4 whichcarries it; The discharge end of each burner 8 is approximately at theinner surface of the wall, The burners '9 discharge the fuel downwardlyinto cavities 12' (Figure 3) in the walls, each such cavity havingadownwardly and inwardly inclined bottom which directs the fuel towardthe center of the furnace. In each burner 9 the fuel leaves the burnerproper through a vertical duct l3 which discharges into the cavity l2therebelow. There is provided an inspection and cleaning opening l4closed by a sliding door l5.

I have not described the details of the furnace supporting structure,cover, I cover seal, cover operating means, etc,, because those detailsdo not constitute the present invention. The furnace may take a varietyof. forms so long as the fuel is introduced into and burned within, orlargely within, the heating chamber.

conduit I6 which'is the subject of my copending 2,407,047. The cover ismounted on tracks I! and for present purposes may be considered as ofconventional design.

Ingots are. as is customary in the art, charged into and discharged fromthe furnace by opening orrolling back the cover and introducing andwithdrawing thev ingots by means of an overhead crane. They may. bearranged in any desired fashion on the hearth 8 within the heatingchamber. The burners are so arranged that the ingots need not bedisposed on the hearth in any particular pattern or relationship to oneanother. The streams of fuel issuing from the respective burnerscooperate to produce a composite swirling flame in rather intimatecontact withthe surfaces of the ingots and which results in uniformheating of the ingots throughout with little or no undesirable washing.

As indicated above, I have found that. the in- I 'troduction of the fueldirectly into the heating chamber as described and the burning of it inintimate contactwiththe' ingots disposed in the heating chamber does notresult ifi increased oxidation or washing; as might be supposed by thosecommitted to the soaking pit theory, but on the' contrary results indecreased oxidation or washing. I believe this to be due, first, to theabsorption of heat from the flame by the ingots themselves, as explainedabove, and, second, to the arrangement of the burners to create auniform swirling flame about and among the ingots.

I can introduce fuel, and air virtually unmixed untilthey come togetherwithin the heating furnace and I find no excessive or harmful scale dueto the action of the oxygen in the air on the ingots. On the contrary,a. relatively thin protective scale is formed which makes for highyield. It is desirable to have a substantial number of burners welldistributed over the furnace walls so as to obtain a thoroughintermixture of the gaseous streams issuin from the various burners.This largely eliminates individual streams impinging on localizedportions of the ingots which might result in hot spots. In find thatingots can be'brought from a given initial tem- The cover 6 is sealed tothe furnace by a water-cooled pipe or perature to a given finaltemperature in less time when heated by my process'and in my fur- I nacethan has been possible previously in the use of soaking pits. This istrue even without preheating the air used in my'furnace. With cold air Ican obtain faster and better quality heating than can be obtained in asoaking pit with preheated air.

Another important advantage of my improved furnace, and which isincident to elimination of the combustion chamber or chambers heretoforeconsidered necessary and always employed in soaking pits, is greatsimplification in furnace design resulting in a large saving in materialand labor in construction and maintenance and in floor space. My furnacecan be preconstructed and transported to the site of erection and placedon prepared foundations thus greatly reducing interruptions in milloperation due to installing the furnace. Of especial value in operation,construction and maintenance is the elimination of radialsupportingbrick covers or thus eliminating dimculties incident toexpanvariously embodied and practiced within the scope of the followingclaim.

I claim: In a soaking pit furnace for heating ferrous ingots, incombination, a rectangular heating 1 chamber having substantiallyvertical opposed walls, a plurality of burners positioned in asubstantially regular pattern over a major portion of the surface ofeach of one pair of said opposed walls and adapted to constitutesubstantially the sole heating source for said furnace and to be inclose proximity to said ingots, a majority of said burners on each ofsaid pair of opposed walls being directed inwardly into said heatingchamber in a direction normal to said apposed walls and adapted toproject unburned combustible material about and among said ingots forcombustion in said heating chamber, the remainder of said burners oneach of said pair of opposed walls being directed downwardly andinwardly into said heating chamber in alternate relation to the burnersin said majority of said burners, said burners on said pair'of opposedwalls being arranged in successive spaced vertical planes substantiallynormal to said opposed walls, whereby ingots placed in said furnace inconventional manner are heated to uniform temperature in intimatecontact with the flames from said combustion of said combustiblematerial,

' CARL H. WEST.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Date copyright 1942, page 223, published by JohnWiley 8: Sons, New York, N. Y.

